How you wish the browser not to cache the configuration file inside an XML file.
adding the following to /etc/httpd/conf/httpd.conf
would help a bit.
# For XML # Force reload <FilesMatch "\.(xml|html)$"> Header set Cache-Control "max-age=60, public, must-revalidate" Header set Expires "Thu, 15 Apr 2010 20:00:00 GMT" </FilesMatch>